Joel Spolsky and Jeff Atwood on Learning C

Stackoverflow Podcast #2, where Joel Spolsky argued that all developers should learn C starting at around 39min. His argument is, that it is like driving with a stick and know about the mechanics, coding in C (or easy-to-use assemble) helps you to understand what's going on under the bonnet, where Jeff does not exactly agree. Has he driven a DSG where it shifts faster than manual? A lot of optimised algorithms in high level languages, garbage collection included, are actually faster than manually coded equivalent by average C coders.